This invention relates to a process for preparing pillared interlayered clays. In another aspect, this invention relates to a process for preparing a pillared clay exhibiting enhanced surface area, enhanced gas storage capacity and improved selectivity in the separation of gases.
The preparation of pillared interlayered clay compositions by reacting a smectite-type clay with an aqueous solution of a suitable polymeric cationic hydroxy metal complex of a metal, such as aluminum, titanium, zirconium and chromium, is well known. Upon dehydration of the reaction product, there results a smectite clay which includes additional metal oxide, such as oxide of Al, Ti, Zr or Cr, in the form of pillars interpersed between the clay layers, as is illustrated in U.S. Pat. Nos. 4,637,991, 4,238,364, 4,216,188 and 4,176,090, herein incorporated by reference. These known clay products having interspersed pillars of metal oxide, such as oxide of Al, Ti, Zr or Cr, (said products being referred to hereinafter as pillared interlayered clays) exhibit advantages in various applications (such as catalytic cracking and gas separation) over untreated (unpillared) smectite clays. However, there is an ever present need to develop improved processes for preparing pillared interlayered clays, in particular processes resulting in pillared clays possessing enhanced surface area and gas storage capacity, and exhibiting enhanced selectivity in the separation of hydrocarbon gases.